398 BOTANY OF SOCOTRA. 



4. HYDROCLATHRUS. 



Hydroclathrus, Bory in Diet. Class, viii. (1825), 419; Ktz. Tab. Phyc. ix. 

 A monotypic genus of tropical and subtropical seas. 



H. cancellatus, Bory loc. cit. ; Ktz. Tab. Phyc. ix. t. 52, f. 2. 



Asjierococcus clathratus, Bory ms. eg J. G. Ag. Sp. Alg. i. 75. 



Socotra. 



Distrib. Of the genus. 



CHLOROPHYCE^E. 



1. ZYGNEMACEJ. 

 1. SPIROGYRA. 



Spirogyra, Link Handb. iii. 262 ; Ktz. Sp. Alg. 437, and Tab. Phyc. v. ; Eabenh. Alg. Europ. 

 iii. 232, f. 73. 



A large genus of fresh water forms distributed all over the world. 



1. S. turpis, Ktz. Sp. Alg. 438, and Tab. Phyc. v. 6, t. 19. f. 2. 



Zygnema malformatum, Hass. Alg. 147, t. 30, ff. 1, 2. 



Socotra. 

 Distrib. Britain. 



2. S. condensata, Ktz. Phyc. Gen. 279, and Sp. Alg. 440, and Tab. 

 Phyc. v. 7, t. 22, f. 3 ; Rabenh. Alg. Europ. ii. 241. 



Conjugata condensata, Vauch. Conf. 67, t. 5, f. 2. 



Socotra. 



Distrib. Europe generally. 



3. S. decimina, Link Handb. 262 ; Ktz. Phyc. Gen. 279, t. 14, f. 2, and 

 Sp. Alg. 441, and Tab. Phyc. v. 7, t. 23, f. 3, and t, 24, f. 1 ; Rabenh. Alg. 

 Europ. ii. 242. 



Socotra. 



Distrib. Europe, Asia, and America. 



